Articles, Quotes & Information

Some materials herein are presented for educational purposes, which we believe to be covered by the Fair Use Doctrine.

Quotes, links, articles, tidbits, etc....this is some of the best information we've found.

• Tubes vs Transistors - Is There An Audible Difference? ( PDF ) by Russell O. Hamm, Journal of the Audio Engineering Society, Sep. 1972 -- Don't miss this paper [PDF] on op-amp distortion comparisons.
• Tubes vs Transistors In Electric Guitar Amps ( PDF ) by W. Stephen Bussey, Robert M. Haigler, Proceedings of the IEEE, Ch. 1610, May, 1981
• The Cool Sound of Tubes by Eric Barbour & IEEE
• Transistors vs Tubes - Feature Comparison adapted from IEEE & Eric Barbour
• Truth In Car Tube Amp Designs - A Schematic Comparison: "A tube bracketed by semiconductors does not nearly comprise a true tube amp."
  
• Milbert Amplifiers and The David Berning Company entries on wikipedia.org.

• Tubes overload and compress comparatively gently, while transistors tend to abruptly clip as they "crash hard into the rails." A guitarist might explain: "At overload, tubes squish and transistors crunch." With several parallels, tubes can be thought of in terms of warm, incandescent light versus transistors as harsh fluorescent light. Not as a rule but generally, transistors make great "digital" switches with hard electrical edges, while tubes are inherently more "analog" and smooth. While some people insist that physical differences are not audible, internally, tubes are mostly vacuum, with a "space charge" or electron cloud that is electrostatically controlled by a varying voltage on a metal grid. Transistors are mostly resistive silicon, purposefully contaminated with impurities to enable conductivity in their crystalline lattice that otherwise insulates.
• Tubes use a charged electron plasma cloud in vacuum, while transistors force audio signal current through something not unlike dirty sand --possibly why 'brittle, hard, sharp, gritty and scratchy' often describe "transistor sound". Whereas rather linear tube circuits are usually simple, most transistor circuits require high negative feedback and more complexity. The All American Five was for decades a popular and common radio, requiring only five tubes. "Transistorization" happened for economy, not better sound --in this case, cheaper was just cheaper. In terms of gracefulness, straightforward simplicity and perhaps ultimately sound quality, transistors fall short.
• "We have called it the Transistor, T-R-A-N-S-I-S-T-O-R, because it is a resistor or semiconductor device which can amplify electrical signals as they are transferred through it from input to output terminals. It is, if you will, the electrical equivalent of a vacuum tube amplifier. But there the similarity ceases. It has no vacuum, no filament, no glass tube. It is composed entirely of cold, solid substances..." - Ralph Bown, Bell Laboratories, upon publicly introducing the transistor in 1947, only a few months after the Roswell incident.

Tubes Vs. Transistors, from newsletter #47 of The Absolute Sound magazine:

"... if you want to try to break across the border into something approaching realism, I still think you have to use tubes." --Harry Pearson, editor

"...tubes are more realistic. They have more bloom; they have more light; they have more body. They do that thing I call 'action,' which solid-state doesn't... tubes just eat solid-state alive." --Jonathan Valin

"... what you almost never get out of a solid-state piece of equipment is a sense of continuousness..." --Harry Pearson

"... there is a subtle but unmistakable sense of roundedness and solidity that tubes have..." --Paul Seydor

"... [tubes] give you the sense of having much more power. A 60-watt solid-state and a 60-watt tube amp never sound equivalent in terms of power." --Harry Pearson

"... I hear more stuff with tubes..." --Jonathan Valin

"You can tell some things from measurements ... but that tells you nothing about how the amplifier communicates the music. You get that from listening." --Robert Harley

• "There is no genuine musical experience without ecstasy." --Glenn Gould [1]
• "Without a doubt, digital was the worst-sounding technical 'advance' of all time; for most of us, it was the first time a technical leap actually sounded worse than what it replaced, if you forget tubes to transistors..." --Stephen St. Croix, Mix magazine, Nov 2005, p.24 MIX Magazine Online
• "There is a clear and distinct difference, and in [30] years of testing equipment, I can't recall any situation where vacuum tubes didn't sound superior to transistors. ... I have always felt the deficiency of the sound of transistor equipment. Knowing this, I have always run a studio full of tube gear. Because of my 30 years' prejudice, I go to great lengths to be sure that this does not bleed over into the listening tests that we do." --Walter Sear, Sear Sound Studios, NY searsound.com
• The Vacuum Tube Rides Again
• Care & Feeding of Vacuum Tubes
• Tube Is Master
• High Tech Low Quality
• Recorded Sound Sucks
• EE's At Fender Put Guitar Amps To Work EE Times magazine, 13Mar2000
• 'Most people can sense and appreciate the subtle differences between a good meal and a great one, while others will deny there are any differences at all without ever tasting the food.' --adapted from George Short, North Creek Music northcreekmusic.com



• I also love to cook and find considerable parallels between cooking and loudspeaker design. Specifically, 1) a simple recipe with the best ingredients is generally better than a complicated recipe with the best ingredients; 2) using the same recipe, the better the ingredients, the better the dish; 3) there are significant differences between the flavor of "identical" ingredients, just like there are significant differences in the sound of "identical" coils, capacitors, and resistors that come from different manufacturers. Also like crossover parts, I have learned that most people can sense and appreciate the subtle differences between a good meal and a great one, while others will deny there are any differences at all without ever tasting the food.' --adapted from George Short, North Creek Music northcreekmusic.com
• "I proposed it would be really cool if we could combine the warmth and depth - tonal realism, if you will - of the sound produced by an audio tube, with one of our state-of the-art motherboards ... Laughter turned into raves a few months later when we did our first lab demo ... The reproduced sound was absolutely amazing. It left everyone stunned." --Al Peng at AOpen America, about the AX4B-533Tube PC motherboard.
• "... then SPL [boom events] took the limelight ... SPL competitions have put us at a bit of a disadvantage ... it became a science: we've taken the entertainment out of it ... spectators are listening to a couple of short spurt burp tones ... nothing more than a few metallic rattles ..." --Paul Papadeas, AutoMedia magazine, May, 2004, pp. 38+, writing on what's wrong with car audio at large.
• "I've been selling home stereo equipment for over 15 years and I've found that when customers listen to a system in the store, 50% of them will prefer the sound of vacuum tubes and 50% will prefer the sound of transistors. But when you let the customer take the equipment home for a trial and play it on their own speakers in a system they are familiar with, just about all of them prefer the vacuum tube sound. It's the transistor equipment that they return. I think it is just because the vacuum tube sound is more pleasant to listen to. It doesn't get on your nerves after a while the way a transistor amp does. The few who prefer transistor sound may not be quite as familiar with the way real musical instruments sound." --stereosalesman, comment posted on digg.com, 10Aug2005.



• "I think people will always respond to emotion and to great songs sung well, and I think the vocalists in particular will always be in demand. There's nothing that approximates the human voice. In the end, when you come down to it, people want to feel something." --Janis Siegel, The Manhattan Transfer
• "I remember being with Stevie Wonder when he got his first Sony 2-track PCM recorder. Man, this thing sounded terrible! Anything it recorded took on a special broken-glass-sliding-on-sheets-of-stainless-steel character. But...it was noiseless and had startlingly low distortion. It was a new and novel sound, to say the least, and Stevie, as a technical pioneer, was committed to using it. Without a doubt, digital was the worst-sounding technical 'advance' of all time; for most of us, it was the first time a technical leap actually sounded worse than what it replaced, if you forget tubes to transistors and transistors to integrated circuits." --Stephen St. Croix, Mix magazine, Nov 2005, p.24
• "Panasonic B-flat Tube CQ-TX5500D is the world's best car receiver with a built-in vacuum tube. Another break-through by Panasonic in 2003 in search of excellence in sound. Ultra high quality amp section with separation in both signal and power for pure sound quality enhancement." --Panasonic advertisement, 2004 [They finally realized what so many have known for so long!]
• "We all know that vacuum tubes are the heart and soul of all legendary amps and are paramounts to their warm, rich tones. So we delved deep into the process of individually measuring every amp and painstakingly analyzing its dynamic properties in every detail. We spent a fortune building up a comprehensive collection of the most popular amplifiers, cabinets and effects in order to thoroughly analyze their tonal aspects, trying to reveal their sonic signatures. Our engineers have spent years getting to understand all there is to know about tube-powered amps, including how different tube types respond under various conditions. They've studied how a tube processes an input signal, how the signal affects other parts of the system, and then modeled them virtually. In vain. ... We started realizing what "tone" means, learning that a guitar amp actually "breathes" and that analyzing frequency diagrams doesn't get you anywhere. Transistors simply couldn't reproduce tube warmth and performance." --marketing blurb from Behringer on its V-Amp Modeler, 2007 (source PDF)

• "Yet technically, the violin playing was perfect. Hi-fi can be like that: perfect in terms of test-bench measurements, but soulless, even clueless, in terms of re-creating the musical experience." --Bill Conrad, Conrad & Johnson, Stereophile, July, 2008, pg. 26
• Who knows? Take a chance. "...and the [now-executive hippie has] got his feet on the desk and he's saying, 'Well, we can't take a chance on this, because it's just simply--it's not what the kids really want, and I'm--I know.' You know, and they got that attitude. And the day you get rid of that attitude and get back to, 'Who knows? Take a chance.' You know, that entrepreneurial spirit where, even if you don't like or understand what the record is that's coming in the door, the person who's in the executive chair [realizes and expects that he] may not be the final arbiter of taste of the entire population, you know." --Frank Zappa on youtube
• Although tube amplification and vinyl records were his special interests, [Harvey "Gizmo"] Rosenberg had soul enough to embrace music in any format. In Gizmo's view, the compact disc, vilified by analog purists, offered limited listening enjoyment primarily because of lack of imagination in the recording studio. "The reason that 90% of the CDs produced are musical gross-outs is because of artistic and intellectual incompetence of producers and engineers, not because of the inherent limitations of the old digital format," he wrote. "Ninety percent of the people who record and produce music haven't got a clue, or don't care, about music quality because their highest musical standard is 'How Will It Sound On The Radio?'" --Harvey "Gizmo" Rosenberg

• "In January 2005 London Underground announced that it would play classical music at stations prone to loitering by youths. A trial had shown a 33% drop in abuse against staff." Apparently, it matters what you hear, and, it probably matters how you hear it. --Wikipedia:London Undeground
• Watching from 8:08 into this video (youtube): Billboard Magazine (23 Jan 1999, Vol. 111 Issue 4, p4), Dr. Richard G. Pellegrino (president of Daydream Productions, an entertainment and consulting company): What's Behind The Subliminal Power of Music: "Brain specialist Dr. Richard Pellegrino declared that music has the uncanny power to '...trigger a flood of human emotions and images that have the ability to instantaneously produce very powerful changes in emotional states...Take it from a brain guy, in 25 years of working with the brain, I still cannot affect a person's state of mind the way that one simple song can." (local and source)
• "Music directly represents the passions or states of the soul: gentleness, anger, courage, temperance...if one listens to the wrong kind of music he will become the wrong kind of person..." --Aristotle (renowned secular philosophers, contemporary of Plato), youtube
• "Good music re-arranges your molecules." --Carlos Santana
• "Studies and Statistics on the Importance of Music Education" by Ryan Sapp, C. Joy Reyes: "Music puts the brain to work in ways other mental functions do not, causing it to grow. ...music actually exercises the brain—not merely by developing specific music skills, but also by strengthening the synapses between brain cells. The synapses control the brain's ability to hear, see, read, understand symbols, speak, use and coordinate muscles, evaluate actions, experience pleasure, and remember. Music makes use of every single one of these systems. ...UCLA brain scan studies indicated that music more fully involves brain functions in both hemispheres than any other activity the researchers studied. The "Mozart Effect" is the most famous of the music/brain research findings...The group listening to Mozart received scores eight to nine points higher from merely a ten listening experience." (local and google cache and source and source) See also Mozart Effect.
• "Music in the Classroom: Its Influence on Children's Brain Development, Academic Performance, and Practical Life Skills" by Jenny Nam Yoon, 2000: "Scientific literature suggests that music is part of one's biological heritage." "A growing body of research reveals the beneficial effects of music on education. Research indicates that music plays an important role in the brain development of a child. Furthermore, researchers believe that children, who have more exposure to music and music training, benefit from enhanced brain activity, which has been shown to increase students' abilities to perform on certain academic tasks. In addition, many practical life skills are acquired through music learning and music training. Therefore, music education is believed to deserve the status as an equally significant core subject. A review of the literature demonstrates the benefits of music education, discussing the influence of music on the child's brain development, academic performance and practical life skills." (local PDF and source PDF)

• "Uh, yes my schooling had a great effect on my musical thinking. It was all negative." --Frank Zappa on youtube

• "As with everything in technology, once the new technology comes in, then people abuse it because they can do things they could never do before. I think we're getting to a point now where we realize that loud is not better. Everything used to be squeezed into this very narrow bandwidth, which meant the quietest and the loudest sounds were not very far apart...When everything is loud...your ears get tired and it creates a kind of energy that maybe you don't want...You don't realize that when you turn it off, there's a relief, because you're agitated emotionally just because it's such a loud sound, like being in a steel factory or something." --George Lucas, Mix magazine, Nov. 2004
• CD vs. LP :: "This finding supports my own subjective impressions comparing the CD against the LP. I much prefer listening to the LP over the CD on my system. The CD sounds dull, congested, muddy, and lacking in dynamics. If I push up the volume, the sound becomes noticeably harsh and artificial. The LP on the other hand sounds more 'dynamic' and 'exciting.'" --Christie Tham, Comparison of CD, DVD, SACD article: part 1 • part 2 • part 3 • part 4
• "Everyone is in love with the way vinyl sounds." --Tom Biery, Executive V.P. for Promotion, Warner Brothers Records, source
• Most pop-culture modern music is artificially hyped up, just like the super nicotine in cigarettes. "Record companies are using digital technology to turn the volume on CDs up to '11'.", source
• "Everything is loud, everything is bright, there's no subtlety in it at all, it's a sound that one would tire of fairly quickly." -- Steven Hoffman, specialist at remastering classic rock albums, source 2007
• "The music available today isn't musical at all. It's best described as anti-music. It's anti-music because the life is being squashed out of it through over compression during the tracking, mixing, and mastering stages. It's simply, non musical. It's no wonder that consumers don't want to pay for the CDs being produced today. .... It's time for all of us in the music industry to wake up! Our musical heritage is being threatened by this wave of anti-music." --Bob Speer, "What Happened to Dynamic Range?"
• "Wimpy, loud sound: All the punch ... is gone, along with much of the feel of the music that comes with some parts being louder than the others. When there's no 'quiet' there can be no 'loud'." --The Loudness Wars explained and demonstrated in under two minutes. A recent Mastering HOWTO showing the focus is all about maximizing loudness. See also Gateway Mastering

Graph showing volume level of 1983 CD: sound is not highly compressed or "maximized": notice the relative differences among the peaks and troughs and how the signal does not fill the entire graph.


Graph showing volume level of 1999 CD: sound is totally ruined: notice how everything is shouting loud (and therefore nothing is relatively quiet) and how the signal is pushed unnaturally (and unnecessarily) to fill the entire graph.


• Turn Me Up -- a non-profit music industry organization campaigning to give artists back the choice to release more dynamic records. The goal is not to discourage loud records but to encourage awareness of and choice for much greater dynamism.
• The Loudness War Analyzed - Paul Lamere, Music Machinery Music & Technology Blog
• Guns 'N Roses: Dynamics And Quality Win The Loudness Wars - Bob Ludwig, Mastering Engineer - Gateway Mastering & DVD
• Fans Complain After "Death Magnetic" Sounds Better On Video Game Than CD - Rock & Roll Daily, Rolling Stone Magazine
• The Death of High Fidelity - Robert Levine, Rolling Stone: Over the past decade and a half, a revolution in recording technology has changed the way albums are produced, mixed and mastered — almost always for the worse. "They make it loud to get [listeners'] attention," Bendeth says. Engineers do that by applying dynamic range compression, which reduces the difference between the loudest and softest sounds in a song. Like many of his peers, Bendeth believes that relying too much on this effect can obscure sonic detail, rob music of its emotional power and leave listeners with what engineers call ear fatigue. "I think most everything is mastered a little too loud," Bendeth says. "The industry decided that it's a volume contest."
• Will the Loudness Wars Result in Quieter CDs? - Tim Anderson, The Guardian: Florida-based recording engineer Charles Dye, whose mixing and recording credits include Bon Jovi, Jennifer Lopez and Shakira, hopes to bring about change with a new initiative called Turn Me Up (turnmeup.org), co-founded with musician John Ralston and studio owner Allen Wagner. The aim is to address the anxiety felt over recordings which are quieter than their competitors.
• Loudness War - Wikipedia
• For Tom Petty Fans, the True Sound of Vinyl, Also Captured on a CD - Robert Levine, New York Times: "Everyone is in love with the way vinyl sounds." --Tom Biery, Executive V.P. for Promotion, Warner Brothers Records
• Why Music Really Is Getting Louder - Adam Sherwin, Times Online
• How CDs Are Remastering The Art Of Noise - Tim Anderson, Guardian Unlimited
• Why New Music Doesn't Sound As Good As It Did - Yahoo! Tech
• The Loudness War - Mark Donahue, Performer Magazine
• Loudness - Chicago Mastering Service

• "The subjective correlation between Total Harmonic Distortion (THD) and what you actually hear is close to zero. After all, a low-fi rack-stereo receiver has far lower THD than the best-regarded triode amplifier. Does that mean that "all amplifiers sound the same?" No, certainly not ... Is the converse true — that measurements are meaningless? No, that's not true either; there are plenty of amplifiers with terrible measurements that do indeed sound terrible. . The fault is not with the subjective perception of the listener, but rather in the measurement itself...you can measure all you want, but a mass spectrometer isn't going to find a lot of difference between lunch at a high school cafeteria and the best dinner at a four-star restaurant. To foolishly assert that the mass-spectrometer is right and the restaurant customers are all deluding themselves is an example of simple ignorance trying to cover its nakedness with the fig-leaf of Science. ... All we can say for certain right now is that simple THD figures are not the right measurement for electronics!" --Lynn Olson, The Sound of The Machine, 1997-2003 ( source )
• Interesting excerpts from Lynn Olsen's "The Sound of the Machine: The Hidden Harmonics behind THD": "...how traditional measurements result in unwise decisions for amplifier design. The lower harmonics are nearly inaudible compared to the upper harmonics, yet they dominate almost any THD measurement! The meter is steering the designer, the reviewer, the dealer, and the consumer away from good sound."
• The Components of Sound A summary of factors affecting sound quality.
• 'Amp Defects Not Covered by Specs' by Norman Crowhurst
• The Perception of Pitch PDF, Frederic L. Wightman, David M. Green, American Scientist vol. 62, Mar. - Apr. 1974, pp. 208-215
• Essential Differences Between Good & Bad Guitar Sound by Dr. Samo Sali, Jul. 2004 salilab.org
• A New Methodology for Audio Frequency Power Amplifier Testing Based on Psychoacoustic Data that Better Correlates with Sound Quality, 2001 Masters Thesis by Daniel H. Cheever PDF An investigation of the hypothesis that accepted measurements of quantifying amplifier fidelity fail to correlate well with subjective sound quality. ... Specmanship rears its ugly head throughout the history of audio. As higher power density output devices (lower cost per watt) became available they were always less linear and so more required more negative feedback to correct. The more feedback, the sharper the onset of clipping, and the more abruptly higher-order audible distortions are introduced.
• The Look of Distortion adapted from Steve Bench
• Sound of Distortion by Jean Hiraga, Glass Audio magazine, May, 2005
• Waveforms, seen and heard in Reason adapted from psylux.com
• Science and Music by Sir James Jeans, Cambridge University Press, 1937: The timbre depends only on the relative energies of the various harmonics and not on their phase-differences. Differences of phase produce no effect on the ear.
• A Future Without Feedback Stereophile magazine, January, 1998:

  "Some aspects of perceived sound quality are not explained by established theory. There is a growing suspicion that some of these aspects --a loss in natural timbre; a duller, less expressive performance; increased aural fatigue; and missing life and energy in reproduced sound-- may be consequences of the application of negative feedback. Many of us working in the audio industry have long been aware that measurements do not fully describe sound quality. Moreover, it seems that measurements fail to describe some of the more important aspects of subjective perception. For example, we may guarantee that an amplifier will have a perfectly flat frequency response under normal conditions of use, yet we cannot explain why it may still sound duller or brighter than another comparably 'flat amplifier.

  "We can measure crosstalk, channel separation, distortion, and noise to incredibly low levels, yet we cannot explain why some amplifiers have greater perceived stereo depth, resolution of detail, and low-level ambiance than others. While we know that 0.3-0.5% of third-harmonic distortion is just audible in the midrange, how can the overall sound of a tube amplifier be judged "just fine" when we can measure 1.5% of second harmonic and 0.8% of third at moderately high listening level? Still more intriguing is the matter of dynamics. Some electronics sound flattened and dulled in terms of musical expression; other may be wonderfully revealing of this quality even at quiet sound levels. Or consider rhythm and timing: One power amplifier gets your foot tapping, another leaves you reading the sleevenotes. I can identify no measurement associated with rhythm or musical dynamics.

• Scientists vs Audiophiles, Stereophile magazine, March, 1999, condensed:

  I'm not claiming that spooky or mystical events occur when you listen to your system. ... Every link in the chain, from the vibration of your stylus to the goose bumps on your arms, is grounded in physical processes. ... But that doesn't mean that we understand exactly what those processes are—especially the ones inside the brain. ...

  You can stand behind complicated truths or you can cling to simple mistakes. Those who feverishly insist that science tells us everything about audio treat science as an exact, finished product. But, any good scientist will tell you that there's much more in the world that we do not understand. Close examination almost always reveals increasing complexity. ...

  Some dissenting scientists and engineers may not immediately appreciate good audio, much as people who go to museums but have no idea why Picasso, Pollock, or Rothko are good painters. They're seeing exactly what everyone sees, but they're seeing it quite differently. ... Some may never be able to see why Picasso is a great painter or appreciate high-end audio; they remain rigid, unconvinced and unconvincible.

• "Substance is something I never appreciated until I had decades of experience under my belt. A discount lens usually offers more features like faster speed or wider zoom range for less money. Likewise, cheaper cars usually offer better specifications, like fuel economy, horsepower or number of radio presets, for a lower price than, say, a Mercedes. You may realize that the Mercedes has a lot more substance and fundamental quality for which there is no numeric specification, and so you probably understand why a Mercedes costs more and delivers in ways not typically measured." -- adapted from Ken Rockwell on photographic lenses, specifications and quality
• THD, Power and Perceived Loudness





• AutoStylin magazine Tech-Corner article ( PDF )
• Think of it as a Sparkplug for your Car Audio System
• Why Tubes?
• Biological and Brainwave Frequency List
• R. G. Keen's article on Using the Carbon Comp Resistor for Magic Mojo
• Weckl, Gadd, Colaiuta and Snare Tuning
• Luke Manley's comments on unusual design

• Milbert Amplifiers offers an official mirror of Frank Philipse's extensive tube datasheet and information archive
• Speaker Wattage vs. Efficiency vs. Sound Pressure Level
• Fantastic site on audio engineering info: Lenard Audio
• Introduction to Sound Recording, Geoff Martin's excellent book online
• How Tubes Work, Briefly - adapted from an article by John Simonton
• Motorola, Lear Jets, 8 Tracks, and Early Car Audio recording-history.org
• "Anyone who has had actual contact with the making of the inventions that built the radio art knows that these inventions have been the product of experiment and work based on physical reasoning, rather than on the mathematicians' calculations and formulae. Precisely the opposite impression is obtained from many of our present day text books and publications." --Edwin H. Armstrong
• "I think a famous French mathematician and physicist was guilty of only slight exaggeration when he said that no discovery was really important or properly understood by its author unless and until he could explain it to the first man he met on the street." --Sir J.J. Thomson
• "...before you attempt to use any effects or tone-shaping devices, you must dial in a flat-response clean tone on the amplifier that you'll be using. I'm positive that most guitarists out there actually use amplifiers that were designed for guitarists (a guitar amp). But did you know that some guitarists prefer to use keyboard amplifiers or even bass amplifiers to help them achieve pristine and pure, clean tones? It's true! The reason it's crucial to attain a pure, clean tone prior to adding other effects to your signal is for better overall tonality. If you can find a clean-sounding amplifier ... then anything that you add to the signal path ... should accentuate what you natural electrified-guitar tone sounds like. Simply put, if your [guitar] sounds good when plugged directly into your amp, anything additional should only improve the sound." --David M. Brewster, "Introduction to Guitar Tone and Effects", page 14
• "Do not place reverb before other effects in a chain, as doing so will add reverb to every subsequent effect -- which tends to sound unpleasant. Do not place overdrive and/or distortion at the end of the chain." --David M. Brewster, "Introduction to Guitar Tone and Effects", page 41
• "Today musicians and sound/studio engineers collectively spend millions on high-dollar rack units and processing gear in order to perfect the quality and clarity of their reverb signals." --David M. Brewster, "Introduction to Guitar Tone and Effects", page 32
• "If you listen to the wrong kind of music you become the wrong kind of person." --Aristotle
• "Good music re-arranges your molecules." --Carlos Santana
• John Atwood's research into the history of world power mains and frequencies: "The frequency of the power we get out of our electric outlets has been fixed since time of our grandfathers or great-grandfathers, at least in the developed world. Yet we are aware that there two standards in the world: 50 and 60Hz, and we may have heard of other frequencies, such as 25Hz, 400Hz, and even DC. One country, Japan, even has both 50 and 60Hz. Where did these frequencies come from? Is one better than the other? What explains the geographical distribution of these frequencies? This article will give the history of the frequencies and try to answer the questions above. ... Early AC alternators were belt-coupled to steam engines, so it was easy to increase the speed of the alternator relative to the engine. For larger and more reliable systems, direct-coupling was needed, but a 133Hz alternator would require many poles. A lower frequency would be better here, but if it was too low, arc lamps would flicker. A frequency of 50Hz was suggested, but it was felt that even this would cause flicker, so 60Hz was chosen. It is rumored that Tesla wanted 60Hz due to his obsession on the number three and all things related to it. In 1890, Westinghouse and Thomson-Houston (one of the predecessors of General Electric) chose 60Hz as a standard for lighting. 50Hz found favor in Britain and Europe, and was used in Southern California (by Southern California Edison) until the late 1940s."
• History of Recording

• Capacitor Field Guide by Harry R. Bissell, Jr., describes types of capacitors, characteristics and applications.
• Interesting article about the foibles of cranky op-amps. Don't miss this paper [PDF] on op-amp distortion.
• Damping Factor by George Augsperger, JBL, Electronics World, Jan. 1967
• Cathode Phase Inversion PDF, Otto H. Smith, 1941
• The Fleming Valve
• Amplifier Fundamentals PDF, AGO 4239A
• An Ultra-Linear Amplifier PDF, David Hafler, Herbert I. Keroes, Audio Engineering, 1951
• Harmonic and Intermodulation Distortion PDF, J. N. A. Hawkings, 1988
• Dave McGowan's interesting research into Laurel Canyon and the "hippie" music scene
• Loudspeaker Nonlinearities – Causes, Parameters, Symptoms [PDF] -- Addresses the relationship between nonlinear distortion measurement and nonlinearities which are the physical causes for signal distortion in loudspeakers, headphones, micro-speakers and other transducers. Using simulation techniques characteristic symptoms are found for each nonlinearity and presented systematically in a guide for loudspeaker diagnostics. This information is important for the interpretation of nonlinear parameters and for performing measurements which describe the loudspeaker more comprehensively. The practical application of the new techniques are demonstrated on three different loudspeakers.

• How Loading And Cables Affect Your Sound And What To Do About It by Howard Davis
  Article clearly describes impedance and cable loading effects; a must-read for guitarists.
• Guitar Effects Pedals - Descriptions, Operations by Howard Davis
  Details what guitar effects are and how guitar effects pedals operate; another must-read for guitarists.
• Wattage, Power, Speaker Efficiency by Howard Davis
  Useful information about power levels, technical specifications, and what it all means: perceived loudness and sound quality.
• All About Bypass by Howard Davis
  Straightforward article covers definitions and features of various types of guitar pedal bypass schemes. p3dals.com pedals incorporate the "total bypass" scheme described in this article.
• You seem to be the only rock personality interested in modernist ... Stravisnky. How do you see--what do you think of their elements? How can you use them? "Well, see, I'm not the only person who might be interested in Stravinsky. There might be some others in rock now who are interested in that kind of music, but I believe I was the first one to bring those composers to the attention of the young record-buying public. The thing that I enjoy about those composers is the harmonic language is a lot more interesting than the normal harmonic language that is used in pop music. You know how Rock and Roll is constructed? You get a guy with a guitar, see? And he knows -- if he's starting -- he knows one, two or maybe three chords. If he's been playing for a few years, he knows ten, twenty, maybe tirty chords. The chords themselves are not interesting because they're standard positions that you put your hand in on the guitar. When songs are made up out of standard things like that, they will tend to sound repetitive; they'll always [sound] the same. So if you're writing for a group of instruments, and each person in that group gets to play one note of a chord, that gives you the chance to make the chord any density that you like. You can only do that by working with many instruments and different tone colors, and so that's what I've come to appreciate ... is the tone colors and the voicings of the chords." --Frank Zappa on youtube
• Malcom Moore's techincal details on guitar pickups

  "Electromagnetic guitar pickups are very poorly understood. This sequential lateral engineering analysis shows how they really work, how to shape the spectrum for any pickup and blows the sales myths beyond reality into figures that are highly predictable! Most of the BLACK ART myths associated with electric guitars are explained and DEMYSTIFIED... To me, there is absolutely no doubt that body/neck resonance plays a major part of colouring the sound from a stringed musical instrument, if the body has, or is, a resonator, but with a solid body guitar the sound is barely resonant and there is minimum inter-string coupling compared to an hollow/resonator body, and further the fact is that simply holding the instrument considerably damps any resonances in both the body and the neck. ... I am well aware that variations in guitar construction can make differences to the sound, but I am far more acutely aware that subtle differences in sound also start with the construction standards of a pickup – not whether it has been dipped in wax or whatever, but by subtle differences in the coil construction or magnetic circuit can make a profound difference to the sensitivity and spectral response of the pickup. "

• Tim Darling's Study of The Edge’s (U2) Guitar Delay

Some materials herein are presented for educational purposes, which we believe to be covered by the Fair Use Doctrine.